Odometer



May 27, 1941- E. MATHER I K 2,243,738

oDolm'rER Filed Feb. 23. 1937 2 Sheets-Sheet 1 Fl' .1 r

- ya 50 Juve/non' Jr@ Ejlflf'ker Patented May 27, 1941 ODOMETEB Irwin E. Mather, Chicago, Ill.. assigner to Stewart- Warner Corporation, Chicago, lll., a corporation of Virgin!! Application February 23, 1937, Serial No. 126,962

(Ci. 'i4-160) Claims.

This invention relates to improvements in electric odometers and particularly to improvements in the construction of odometers rendering them more economical to manufacture and more satisfactory in operation.

Electric odometers are now available to owners of automotive vehicles, but are not extensively used because of their cost as compared to the cost of other types. The present invention is directed particularly to the type of odometer that utilizes an electromagnetically operated pawl and ratchet mechanism for imparting intermittent one-way movement to a rotatable indicia-carrying member. In this type of odometer the electromagnetic means is energized periodically as the vehicle travels and the movement imparted to the indicia-carrying member is directly proportional to the distance travelled by the vehicle.

The primary object of the present invention is to provide a new and improved odometer that is substantially noiseless in operation and which can be manufactured very simply and economically.

Another object of the invention is to provide a new and improved electromagnetic operating means for the odometer.

A further object of the invention is to provide a new and improved pawl and ratchet mechanism adapted intermittently to be actuated by the electromagnetic actuating means and so constructed and arranged with respect to the actuating means that these two parts may be readily assembled to form a unit that is noiseless, rugged and dependable in operation.

An ancillary object of the present invention is to provide an improved housing and support for the electromagnetic actuating means and the indicia-carrying member.

Further objects and advantages of the present invention will become apparent from the ensuing description of an illustrative embodiment of the invention.

In the drawings:

Fig. 1 is a top plan view of an odometer embodying the present invention, showing diagrammatically the manner in which the electromagnetic actuating means forming a part thereof may be connected to a moving part of the vehide:

Fig. 2 is a horizontal section through the odometer illustrated in Fig. l;

Fig. 3 is an irregular longitudinal vertical section, taken on line i--I of Fig. l;

Fig. 4 is a transverse vertical section, taken on line 4-4 of Fig. l:

Cil

. scribed hereinafter.

Fig. 5 is a transverse vertical section, taken on line lof Pig. l. with the rotatable indiciacarrying member omitted therefrom;

Fig. 6 is an enlarged partial side view showing the details of the mounting for the indicia-carrying member and ratchet wheel;

Fig. 7 is an enlarged partial top plan view of' theipawl and ratchet mechanism shown in Fig. 3; an

Fig. 8 is an enlarged partial bottom plan view gli trae pawl and ratchet mechanism shown in Referring particularly to Figs. 1 and 2 of the drawings, there is shown an odometer indicated generally by reference numeral Il, comprising a translating device I2 and an indicia-carrying member Il intermittently rotated thereby in a single direction by means of a pawl and ratchet mechanism Il. The translating device consists of a solenoid coil it wound of a large number of turns of relatively small diameter wire and an amature Il made of any suitable magnetic material and adapted to actuate the pawl and ratchet mechanism Il in a manner to be fully de- The coil I6 is connected by lead wires I9 and 2l to terminal clips 2| and 22, respectively, secured in suitable manner to binding posts 23 and 2l, respectively, mounted in spaced-apart relation to each other on a terminal board 25 made of any suitable insulating material. Binding postA 2l is connected by a conductor 20 to a normally open cam-actuated switch 21 and the latter in turn is connected by a conductor 28 to ground 29. Binding post 24 is connected by a conductor Il to one terminal of a diagrammatically illustrated ignition switch 3l usually mounted on the dashboard of a vehicle. The other terminal of the ignition switch is connected by a conductor 32 to a storage battery 33 and the latter is connected through conductor 3| to ground l5. 'Ihe cam actuated switch 21 is periodically closed by cam driven by a shaft 3l connected to any suitable moving part of the transmission of the vehicle. As the cam rotates an obvious energizing circuit for the coil I6 is closed periodically and it is apparent that this circuit is closed each time the vehicle travels a predetermined distance.

'I'he terminal board 25 is secured to a metallic base plate 4l by a pair of screw bolts 4i and the terminals are insulated therefrom by a strip of insulation l2 separated from the terminal board by spacing washers I3. The lead wires I9 and 2l are insulated from the base plate 40 by bushings 44 and 45 pressed into the openings in the base plate through which these wires extend. The coil I6 is securely held in place by means of the previously mentioned base plate 40, a substantially cylindrical outer casing 46 and a cover plate 41. The casing 46 and the end plates 40 and 41 are held in abutting relationship by fingers 48 formed at the ends of the frame and extending through complementary openings 49 on the end plates. These fingers are provided with transverse openings through which Wedge-shaped pins 50 are driven securely to hold the parts together.

The coil is spaced from the end plates 40 and 41 by a pair of insulating washers 52 and from the outer casing by a wrapping of insulating material 53. A layer of insulation 54 also separates the coil from a central brass spacing tube 55 closely surrounding the armature I1 and acting as a guide for it in its movements. The spacing tube 55 is secured to the cover plate 41 by a press fit therebetween and the centrally located aperture 56 formed on the cover plate. The tube 55 is also rigidly secured to the bottom plate 40 by means oi a brass tube 51 upon which it is pressed and which in turn is pressed into a centrally located aperture in the base plate.

It may be noted from Figs. 2 and 3 that the tube 51 extends slightly less than half the length of coil I6 into the tube 55 and that it closely surrounds an intermediate portion 58 of a longitudinal pin 59 extending through and upon which the armature is mounted. The intermediate portion 58 is formed with a diameter slightly greater than that of portion 59, thereby forming a shoulder against which the armature abuts. The other end 68 of the pin 59 is made with a somewhat smaller diameter' than the intermedi-- ate portion and extends through a guiding bushing 6i of insulating material pressed into tube 51.

The armature i1 is sup-ported at its left end by a resilient iiexible arm 63 adapted to bias the armature for movement away from the coil and secured by screws 64 to a pair of shoulders 65 formed at the lower end of one of a pair of integral arms 66 and 61 extending outwardly from the cover plate 41. rIhese arms, together with the cover plate, form a substantially l.)- shaped bracket for the support of the armature, the pawl and ratchet mechanism it and the indicia-bearing member i3. The flexible arm 63 is provided with a circular opening 68 to give it greater flexibility. Mounted for movement with the armature and flexible arm is a substantially circular brass disc 69 provided with a triangular iianged extension 18 upon which is secured a pawl 1| made of resilient spring steel and constructed in a novel manner to be described hereinafter.

'The flexible arm 63 and disc 69 are separated from each other by an insulating Washer 12 and are secured for movement with the armature by a nut 13 secured to the end of pin 59 and bearing against a brass disc 14 also separated from the flexible arm by an insulating Washer 15. The movement of the armature I1 away from the coil I6 by the flexible arm 63 is limited by a stop arm 16 also secured to the shoulder 65 by the screws 64 and separated from the flexible arm thereat by insulating strips 11. The stop arm 16 is provided with a circular aperture 18 aligned with the armature so that it will not limit movement thereof.

In order to render the electromagnetic actuating means just described substantially noiseless in operation, its movement in both directions is limited by noise-absorbing material such as cotton washers 19 suitably secured, as by shellac, to the outer side of cover plate 41 and the inner side of stop arm 16, respectively.

The indicia-bearing member I3, the component cylinders 8| of which are rotatable about a shaft 82 fixed to the arms 66 and 61, may be of any Weliknown construction. It may be constructed as shown in the copending application of Le Fevre et al., Serial No. 754,522, filed November 23, 1934, and assigned to the assignee of the present application. Preferably it is of a type therein disclosed in which the cylinders, with the exception of cyinder 83, are rotated a unit distance only when an adjacent cylinder has rotated through 360 degrees and in which al1 cylinders are spaced by gear mounting spacers 84 held against rotation in either direction by a shaft 85 also mounted in the arms 66 and 61.

The spacers 84 are provided with V-shaped portions 86 ((see Fig. 3) fitting over the shaft 85 when the indicia-carrying unit I3 is assembled on arms 66 and 61. The indicia-carrying memben just described is assembled by iirst placing shaft 85 on the arms 66 and 61 and then placing one end of shaft 82, on which the cylinders 8| and 83 are mounted, into an openingin arm 61 and then sliding the opposite end along a groove 81 (see Fig. 6) formed on arm 66. The shafts are held in place on arm 6B by a washer 88 provided with diametrically opposed radial openings 89 and 9D adapted to fit around the projecting ends of 82 and 85 of shafts 82 and 65, respectively. The washer' 88 is suitably secured to the aim 66, as by a screw bolt 9|.

The indicia-bearing cylinders are driven by a ratchet wheel 93 of novel construction. The wheel is constructed of a plruality of relatively thin sections made of a phenolic condensation product. 'In the illustrated embodiment (see particularly Figs. 3 and 7), the wheel consists of a toothed center section S4 and outer sections and 96 having smooth peripheral faces. The

portion 94 are of an unteeth 91 of the tooth usual shape in that the portion 98, engaged by the pawl 1I on its down stroke, is made with an obtuse angle so that there is no danger that the pawl 'il will slide off the tooth as it is drawn toward the coil by the armature.

In order to make the operation of the pawl and ratchet mechanism quieter, the sections 95 and 96 of the ratchet wheel are made with an outside diameter somewhat larger than the root diameter of the toothed portion 94. By so constructing the ratchet wheel, the movement of the pawl 1| toward the axis of rotation as it is moved upward and over a tooth is restricted so that it does not strike the ratchet wheel with as much force as it would otherwise.

Referring now more particularly to Fig. 7, it will be seen that the pawl 1I is substantially rectangular in shape and is provided with a rectangular centrally located aperture I8I having a Width slightly greater than that of the toothed portion 94 of the ratchet wheel. The outer end of the pawl is bent outwardly as indicated at |02 so that the pawl rides on the smooth portions 95 and 96. When the pawl is moved upward by the flexible resilient arm 63 from the position illustrated in Fig 3, the bent portion |02 rides over the particular tooth thereunder at that time.

Retrograde or other undesired movement of the indicia-carrying member is prevented by a second apertured rectangular member |03 similar in all respects to pawl 1|, but mounted nearer to the ratchet wheel upon a flange |04 formed integral with arm 61. By positioning the member |03 nearer the ratchet wheel so that the central portion thereof bears against the smooth portions 95 and 96 of the ratchet wheel, the member presses against the ratchet wheel and thereby frictionally prevents movement of the ratchet wheel except when the latter is actuated in a predetermined direction by the pawl.

It is believed that the operation of the odometer will be apparent from the above description, but it may be reviewed brieiiy at this point. The odometer will remain inoperative as long as ignition switch 3| remains in its open position. However, when the ignition switch is closed, the circuit for the operating coil I6 is conditioned for closure by the cam-actuated switch 21 so that when the switch 21 is periodically closed by the cam 36 the coil is accordingly periodically energized.

The normal position of the amature is illustrated in Fig. 2. In this position the armature and disc 10 attached thereto are held against the cotton washer 19 on the underside of stop arm 16. When the coll is energized, the armature I1 is pulled toward the coil by magnetic attraction until the pawl-carrying disc 69 is stopped by the cotton washer 19 on the outer side of cover plate 41. When the energizing circuit is opened again, the armature is moved back to its initial position by the flexible resilient arm 63. The periodic reciprocation of the armature y results in a similar movement of pawl 1|, which imparts one-way movement to the ratchet wheel 93 in an obvious manner. On release of the armature and movement thereof by the flexible arm 63, the portion |02 of pawl 1| rides over a tooth so that upon subsequent downward movement of the armature by energization of the coil, the pawl 1| rotates the ratchet wheel a unit distance.

The arrangement described is very rugged in construction and is not affected by vibrations transmitted thereto by the vehicle when the vehicle is travelling over a rough road. The undesired movement of the ratchet wheel is prevented under these conditions by the member |03 pressing against the ratchet wheel.

The odometer may be readily assembled and disassembled in case repairs are necessary. In order to disassemble the unit it is necessary only to remove the pins 50 from the openings in nngers 48 and the various parts of the odometer become readily separable. Furthermore, the actuating and indicating means of the odometer may be assembled separately at different places and thereafter assembled to form a single unit at any desired location.

The ratchet wheel of the described embodiment is provided with forty teeth and the pawl is adapted to be actuated a like number of times when the vehicle moves a miie. The use of this comparatively large number of teeth reduces the stroke of the pawl and armature and, therefore,

also reduces the power necessary to operate the odometer.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

l. In a pawl and ratchet mechanism, the combination including a multiple section ratchet wheel comprising a toothed section and a section having an outside diameter greater than the root diameter of said toothed section and smooth peripheral surface, a pawl constructed of resilient material having a portion adapted to engage said teeth to impart movement to said wheel and another portion adapted to engage said smooth portion to define the point of engagement between the pawl and teeth, and a resilient member adapted to bear against said smooth peripheral surface to prevent rotation of the wheel except when moved in a predetermined direction by said pawl.

2. A pawl adapted to be used with a ratchet wheel having toothed and smooth peripheral portions comprising, in combination, a portion adapted to engage said toothed portion when actuated in a predetermined direction for imparting movement to said wheel, and a portion adapted to engage the smooth portion of said wheel to denne the point of engagement between said teeth and tooth-engaging portion.

3. A pawl for use in a pawl and ratchet mechanism comprising a ratchet wheel having a toothed central and smooth outer peripheral portions, including in combination, a substantially rectangular strip of resilient material provided with a substantially rectangular centrally located aperture of a width greater than the width of the teeth on the ratchet wheel, the portions of said strip adjacent the aperture being adapted to ride on the smooth portions of said wheel, the forward end of said pawl being curved away from said wheel at the point of engagement whereby said end of the pawl will readily engage the teeth when moved in a predetermined direction and slide over the teeth when moved in an opposite direction.

4. In a pawl and ratchet mechanism, the combination including a multiple section ratchet wheel comprising a toothed section and a section having a smooth peripheral surface, a pawl constructed of resilient material having a part adapted to engage said teeth to rotate said wheel and another part adapted to engage said smooth portion to define the point of engagement between the pawl and teeth, and a resilient member adapted to bear against said smooth peripheral surface to prevent rotation of the wheel except when moved in a predetermined direction by said pawl.

5. In a pawl and ratchet mechanism, the combination including a ratchet wheel provided with peripheral toothed and smooth portions, said toothed portion being located between two smooth portions, a pawl provided with a part adapted to engage said toothed portion for rotating said wheel in a predetermined direction and parts adapted to engage said smooth portions to deiine the point of engagement of said tooth engaging part with the teeth on said toothed portion, and a friction member adapted to engage said smooth portions for preventing movement of said wheel except when actuated in said predetermined direction by said pawl.

IRWIN E. MATHER. 

